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71 lines
2.2 KiB
JavaScript
71 lines
2.2 KiB
JavaScript
import { logger } from './logger.mjs';
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// currently duplicate with core util.mjs to skip dependency
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// TODO: add separate util module?
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export const tokenizeNote = (note) => {
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if (typeof note !== 'string') {
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return [];
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}
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const [pc, acc = '', oct] = note.match(/^([a-gA-G])([#bsf]*)([0-9]*)$/)?.slice(1) || [];
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if (!pc) {
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return [];
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}
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return [pc, acc, oct ? Number(oct) : undefined];
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};
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const chromas = { c: 0, d: 2, e: 4, f: 5, g: 7, a: 9, b: 11 };
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const accs = { '#': 1, b: -1, s: 1, f: -1 };
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export const noteToMidi = (note, defaultOctave = 3) => {
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const [pc, acc, oct = defaultOctave] = tokenizeNote(note);
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if (!pc) {
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throw new Error('not a note: "' + note + '"');
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}
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const chroma = chromas[pc.toLowerCase()];
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const offset = acc?.split('').reduce((o, char) => o + accs[char], 0) || 0;
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return (Number(oct) + 1) * 12 + chroma + offset;
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};
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export const midiToFreq = (n) => {
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return Math.pow(2, (n - 69) / 12) * 440;
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};
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export const clamp = (num, min, max) => Math.min(Math.max(num, min), max);
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export const freqToMidi = (freq) => {
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return (12 * Math.log(freq / 440)) / Math.LN2 + 69;
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};
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export const valueToMidi = (value, fallbackValue) => {
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if (typeof value !== 'object') {
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throw new Error('valueToMidi: expected object value');
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}
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let { freq, note } = value;
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if (typeof freq === 'number') {
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return freqToMidi(freq);
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}
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if (typeof note === 'string') {
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return noteToMidi(note);
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}
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if (typeof note === 'number') {
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return note;
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}
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if (!fallbackValue) {
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throw new Error('valueToMidi: expected freq or note to be set');
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}
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return fallbackValue;
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};
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export function nanFallback(value, fallback = 0, silent) {
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if (isNaN(Number(value))) {
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!silent && logger(`"${value}" is not a number, falling back to ${fallback}`, 'warning');
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return fallback;
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}
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return value;
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}
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// modulo that works with negative numbers e.g. _mod(-1, 3) = 2. Works on numbers (rather than patterns of numbers, as @mod@ from pattern.mjs does)
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export const _mod = (n, m) => ((n % m) + m) % m;
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// round to nearest int, negative numbers will output a subtracted index
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export const getSoundIndex = (n, numSounds) => {
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return _mod(Math.round(nanFallback(n, 0)), numSounds);
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};
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